Questions tagged [loops]

The tag has no usage guidance.

Filter by
Sorted by
Tagged with
2
votes
2answers
41 views

Does any algorithm loops at some point?

Given that any implementable algorithm has a finite number of internal states, and given that any state is determined by the previous one, does that implies that any algorithm loops at some point? If ...
-1
votes
0answers
7 views

Class inheritance hierarchy

Consider the inheritance hierarchy shown below. Each part of this question is independent. ...
0
votes
1answer
26 views

I cannot find an invariant for the following program

I have the following: (|$y=0; x=c$|) while(x > 0){y=y+a; x=x-1;} (|$y= a*c$|) This seems like a fairly simple program and I can intuitively tell that the post ...
0
votes
0answers
34 views

How to draw flowchart for if condition within nested loops?

Please find my program logic as below : Please find my flowchart for the above program logic as below: My superior asked me correct the flowchart. But I couldn't identify my mistakes. Please guide ...
0
votes
1answer
52 views

Time Complexity of the below code? [duplicate]

here is a nested loop where all the variable are integers.This is another question to the thread. I understood the solution part , but stuck in the time-complexity part. What is the time complexity ...
0
votes
0answers
23 views

Using induction vs invariants to prove correctness of algorithms

In my algorithms class I have generally been proving algorithms by induction. So for example, given some algorithm $A(n)$ that computes $x$, I show that the algorithm works for some base case, say $A(...
1
vote
1answer
65 views

Running time of algorithm (effect of j*j in for loops) - Theta Runtime

In Theta notation what are the running times of these algorithms? Algorithm 1 for i=1..n j=1 while j*j <= i: j = j + 1 Since the outer loop ...
1
vote
1answer
28 views

Runtime-Analysis for single loop incremented by a factor of 3

So, I'm trying to understand how to get the run time of this loop: for(int i = 1; i < n*n*n; i*=3) {...} So, far I know: loop starts at 1 finishes when $i &...
1
vote
1answer
27 views

What is an array that can be iterated circularly an infinite amount of times called?

I have a feeling that the answer is either a "circular linked list" or a finite state machine, but the answer is probably a circular linked list.
1
vote
3answers
102 views

Dealing with test condition '=' for a while loop when determining a bound function/loop variant

The following is the definition of what a bound function for a while loop must satisfy: The bound function is an integer-valued, total function of some of the inputs, variables and global data that ...
1
vote
1answer
320 views

is a while loop always an indefinite loop?

Building on this example and others found elsewhere we have two types of loops, definite and indefinite: definite being a loop that has its number of iterations known before it is executed. E.g. a ...
0
votes
1answer
61 views

algorithm analysis - complex dependant nested loop

First of all, I know there are many questions like this on the site. But I think this case is a bit different. Consider the following code: ...
0
votes
3answers
32 views

Relative efficiency of n tasks in 1 loop vs. 1 task each in n loops?

Say I have 3 simple tasks, to find the min, the max, and the average of an array of numbers. A modular approach would be to write one function for each, thus iterating over the array thrice. However, ...
-1
votes
1answer
98 views

What would be the big-o time complexity of this scenario? [duplicate]

I am wondering what the time complexity of a for loop that increments the control variable, but also multiplies it inside the loop. For example ...
0
votes
0answers
23 views

Run time analysis of inner loop [duplicate]

What is the run time of the following piece of code in Big-Oh notation? The first loop runs n times in the worst case. But I am having difficulty in finding run time of nested loop which runs V / deno[...
0
votes
1answer
47 views

What will be big O complexity for this loop? [duplicate]

I am not able to understand time complexity of this for loop. While outer loop is O(n) the inner loop jumps certain calculation. How to find the complexity? ...
2
votes
2answers
69 views

Quotient in LOOP program [closed]

I want to construct a LOOP-computable program for the integer division (quotient): x = a DIV b The LOOP specification can be seen here: https://en.wikipedia.org/wiki/LOOP_(programming_language) I ...
0
votes
1answer
57 views

Time complexity dependent on magnitude of input [duplicate]

I'm trying to analyze an algorithm that looks like this: def foo(L): for n in L: for x in range(n): ... What would be its time complexity?...
1
vote
1answer
158 views

Find the efficiency class

I have to find the efficiency class of this algorithm b = 3 a = 4 for i = 4 to n^2 if (i mod 2 == 0) a = a+2 else b = b*3 end for I ...
0
votes
1answer
398 views

Big-O notation for nested loops that might skip iterations

When you have an algorithm that may skip a lot of iterations due to a hash table lookup, do you still count the iterations that are exited immediately? Hypothetical example: ...
-1
votes
1answer
248 views

Finding time complexity when while loop included [duplicate]

There are two sorted arrays nums1 and nums2 of size m and n respectively. Find the median of the two sorted arrays. Example 1: nums1 = [1, 3] nums2 = [2] The median is 2.0 Example 2: nums1 = [1, ...
6
votes
5answers
3k views

How can a computer run an infinite loop?

I understand the concept behind for and do/while loops, but I am trying to understand what is happening at the hardware level that allows a loop to run infinitely. Technically wouldn't it have to stop ...
-1
votes
1answer
75 views

Measuring infinite loops [closed]

Theoretically, is there a way to measure how many infinite loops are running at a given point in time? In other words, is there a way to freeze everything and get a number on how many infinite lines ...
-1
votes
1answer
180 views

What is the procedure to find the time complexity of python program? [duplicate]

Is there any kind of function which is used in python to calculate the time complexity of another function?
1
vote
1answer
81 views

How do you solve this [1,5,9,4] pair numbers problem?

So given an array of [1,5,9,4], find all pairs of numbers that can sum/subtract/divide/multiply to another number in the array(that number is not part of the pair), and return the total count of pairs ...
1
vote
0answers
23 views

Nested Function stuck on iteration update

I want to solve the Sparse Extended Information Filter Slam described by Dr. Sebestian Thrun in Probabilistic Robotics.I stuck in some nested function. The algorithm is described in page 309 in this ...
0
votes
1answer
126 views

Exponential nested Loop Big O complexity calculation [duplicate]

Can I get a bit of help over here, I can't seem to get to a finish point with this code complexity. I have trouble with making notations, exponential ones in particular..... I spent hours with this ...
1
vote
1answer
54 views

What changes do I need to make to my algorithm to make this scene from a different angle? [closed]

The code below is in F#. It creates a scene which looks like a perspective coming from the top left. I thought if I would change i % j = w then it would come from ...
5
votes
0answers
221 views

How Janus (Reversible Programming Language) `if`, `while`, and Update Work

In Reversible Computing, all program statements are reversible. I understand for example that the following: \begin{align} x\ {+}&{=}\ 4\\ y\ {*}&{=}\ x\\ x\ {-}&{=}\ 10 \end{align} Has ...
2
votes
1answer
293 views

Why does the insertion-sort algorithm have a quadratic instead of a quasi-linear time complexity?

Can someone explain how the insertion sort have quadratic time complexity and not quasi-linear time complexity in the worst-case? Even in the case of a reversely sorted list, it's not like it'll have ...
0
votes
3answers
42 views

What is the most used way to write for-loop as pseudocode?

for $e\leftarrow1$ to 8 do for $e\in[1,8]$ do for $e\in\{x\in\mathbb{N}|1\le x\le8\}$ do What is more preferred?
0
votes
0answers
88 views
1
vote
1answer
1k views

Runtime analysis of while-loop analysis

s = n while (s > 4) s = s / 2 else s = s - 1 Let $T(n) = \Theta(S(n))$ where $S(n)$ is number of while-loop runs. $S(n)=1 + S(n/2)$ if $n$ is even $S(n)=...
2
votes
1answer
100 views

Big Oh notation for a function with two inputs of linear growth

I'm quite new to time-complexity analysis so I might have misunderstood some basic concepts but lets say we have the following function: ...
1
vote
1answer
99 views

Loop termination - Loop invariant

(x >= 0 && y >= 0) q = 0; r = x; while ( r >=y ) { r = r - y; q = q + 1; } (x = q*y +r) && (r >= 0) && (r < y) For ...
1
vote
0answers
29 views

Scheduling loop

I do not understand how do you write schduled loop from unscheduled one. The unscheduled loop straightforward if you follow the stall rules. The rules say you are supposed to stall after L.D but in ...
-1
votes
1answer
34 views

Little bit confusing to compute time complexity of nested loop [duplicate]

1 for(i=1; i<=n; i++){ 2 for(j=1; j<=n; j*=2){ 3 a[i][j]=b[i][j-1]+1; 4 } 5 } line 1 : n+1 times lnie 2 : n/2+1 times line 3 : constant time c ...
3
votes
1answer
85 views

time complexity when power is involved in iteration

How do I calculate the time complexity of the following method? Would you please provide explanation? I know it's going to involve sqrt(n) * <something>. I ...
1
vote
2answers
682 views

Time complexity of euler totient function

Code for finding $\phi$(n) is ...
1
vote
2answers
642 views

Solving complexity using summation

I have the following algorithm: func() { for(i=1; i<n; i=i*2) print("aa"); } How can I find Big-Oh using summation?
1
vote
1answer
579 views

Complexity of while loop using series

For the following code fragment: i = 1; s = 1; while(s <= n) { i++; s = s+i; printf("x"); } How can we go about proving the time complexity of ...
0
votes
1answer
90 views

Complexity of a loop

If the body of a simple for loop has time complexity $O(n)$ and it is executed $n-1$ times what is the time complexity of the complete loop? I am trying to figure out the correct answer to this ...
1
vote
1answer
314 views

Run Time of Nested Loop

In the following loop for i = 1 to n doSomething O(1) for j = 1 to k doSomething O(1) Is the runtime still $O(nk)$ even with the expression in ...
0
votes
0answers
83 views

How many operations does this algorithm require?

I have the following algorithm x = 0 S = {} k = 1 while x + a[k] < n do S = S + {k} x = x + a[k] k = k + 1 end where ...
0
votes
1answer
45 views

Loop Transforms to Increase Parallelism

I have the need to parallelize as much as I can (in order to make it run fast) the following part of an algorithm: ...
2
votes
1answer
2k views

Recursion call inside a for loop time

I'm analyzing a piece of code that has a recursive call inside a for loop such as: ...
1
vote
1answer
1k views

Find Number of even subarrays $O(n)$ [explanation needed]

So I found a solution to this problem here http://marcodiiga.github.io/number-of-even-sum-subarrays but I am unsure of exactly how it works. I get the premise that in order to have an even sum it must ...
1
vote
1answer
442 views

How to get Loop invariants to prove program is correct in Hoare logic

start off stating the definition of a loop invariant. It is a condition that must be true at the start of the loop and must be true after each iteration of the loop. I understand what it is but i have ...
0
votes
2answers
514 views

what is halting problem? [duplicate]

i have researched it on wikipedia and it produces me an unusual example and stories about Turing,so what i understand is if an program run in loop,an electronic device in cpu or in computer structure ...
0
votes
0answers
192 views

Run time analysis of a program with nested for loops

Problem Let's say we are given a program and we want to find an algorithm that analyses its asymptotic complexity. This program can only have two types of statements: ...